1. Field of the Invention
The present invention relates to speech processing, and more particularly, to a speech converter that modifies various aspects of a received speech signal according to a user-selected one of various preprogrammed profiles.
2. Description of the Related Art
Speech conversion is a technology to convert one speaker's voice into another's, such as converting a male's voice to a female's and vice versa. Speech conversion systems are a new concept, most of which are still in the research phase. The SOUNDBLASTER software package by Creative Technology Ltd., which runs on a personal computer, is one of few known sound effect products that can be used to modify speech. This product utilizes an input signal comprising a digitized analog waveform in wideband PCM form, and serves to modify the input signal in various ways depending upon user input. Some exemplary effects are entitled female to male, male to female, Zeus, and chipmunk.
Although products such as these are useful for some applications, they are not quite adequate when considered for use in more compact applications than personal computers, or when considered for applications requiring more advanced modes of speech conversion. Namely, personal computers offer abundant memory, wideband sampling frequency, enormous processing power, and other such resources that are not always available in compact applications such as wireless telephones. Depending upon the desired complexity of conversion, it can be challenging or impossible to develop speech conversion systems for applications of such compactness.
An additional problem with known speech modification software is the converted speech does not always sound natural. Although the reason for this may not be unknown to others, the present inventor has discovered that the problems lies in the application of the same conversion to speech qualities such as pitch and formants.
Consequently, known speech conversion systems are not always completely adequate for all applications due to certain unsolved problems.